It all started on an autumn evening in 2012 at a charity event on the rooftop of a Los Angeles hotel. I bumped into "Wipeout" host John Henson, and introduced myself as a "Nightline" producer and therefore a distant cousin from the same ABC family.

"You work for 'Nightline.'" he said, leaning in, "Then I have a story for you."

Little did I know that the story that I was about to hear would send me on a year-long journey to discover complex and multi-layered truths tangled up in a web of lies.

The story went like this. Henson had just spent two weeks in an emotional email back-and-forth with a distraught mother about to lose her daughter to a severe type of childhood cancer called neuroblastoma. She said her daughter Scarlet, a "Wipeout" fan, had begged her to get in touch with the show's host.

Later on, when Henson shared the email correspondence, I saw how personal it had become. There were photos of a beautiful little girl in the hospital. There were pictures of journal pages and drawings created by 8-year-old Scarlet just for him. And some of the emails even came from the dying girl.

"I have cancer very bad and the doctor cant [sic] fix me so i [sic] get to get angel wings and go to heaven," Scarlet emailed.

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PHOTO: "Wipeout" host John Henson said a woman reached out to him over email, posing as a mother who had a dying daughter. Henson received pictures of journal entries and drawings from a girl named "Scarlet" but it all turned out to be a hoax.

But then the story started to unravel when Scarlet's mother, Katherine, was unable to provide information about the doctors involved with Scarlet's care that Henson, growing cautious, asked her to share.

"I am sorry if we gave you reason to doubt," the mother wrote. "I can't imagine someone making up something like this but then again I am not in your line of work. ... I'm exhausted and emotional. I will email you the contact information for her oncologist as soon as I speak with him, until then I will ask Scarlet not to contact you. I will tell her you're busy. I need to protect her heart as well."

Once the red flags went up, Henson turned over the emails to an old family friend who is now a private investigator. Almost immediately, the private investigator saw that it was a hoax. The photos of the sick girl were, in fact, of a real girl who lost her battle with neuroblastoma in 2007 at the age of 9. The photos had been lifted straight off of memorial blogs.

"But why?" I asked Henson. He told me that while the woman he had been communicating with had not yet asked for money, he could only assume that the end game was a nefarious financial scam. He told me that he had learned that the scam was so sophisticated that some of the metadata buried in the photographs even pointed to a location in Mongolia.

Armed with dozens of emails and photographs, I decided to try to find the person or people responsible. The IP address from the Yahoo email account belonging to the mother seemed to show that the emails came from Wyoming, but that did not seem to help much. I retraced the private investigator's footsteps, extracting metadata, including GPS coordinates, from the newer images, including the journal entries.

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PHOTO: "Wipeout" host John Henson said a woman reached out to him over email, posing as a mother who had a dying daughter. Henson received pictures of journal entries and drawings from a girl named "Scarlet" but it all turned out to be a hoax.

When I first entered the GPS coordinates into Google Maps, Mongolia turned up. But then I discovered that certain types of longitude numbers require a negative sign to register correctly, and I tried again. And bingo, there was an exact street address: 206 Walnut St. in Douglas, Wyo., about an hour outside of Casper.

It was the address for the historic Hotel LaBonte, which also rents out apartments for short- and long-term stays, often to people who are drawn to the area to work in the oil industry.

I was not quite ready to buy a ticket to Wyoming, so instead, I called the local police to ask if they knew of anyone around town who had been talking about a sick kid.

As I described the person I wanted to find, the lieutenant on the other end of the line grew silent.

"We did work a similar case," he said eventually. And while he said he could not reveal anything further, he said that I might find what I was looking for if I followed up with the county prosecutor. From that tip, I was able to get a name: Hope Jackson.

A most helpful district court clerk agreed to find Hope Jackson's case file and read its contents to me over the phone.

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PHOTO: "Wipeout" host John Henson said a woman reached out to him over email, posing as a mother who had a dying daughter. Henson received pictures of journal entries and drawings from a girl named "Scarlet" but it all turned out to be a hoax.

As the clerk read a statement from the arresting officer, Kevin Lovewell, to borrow a phrase later used by one of Jackson's celebrity victims, my jaw dropped.

"I was contacted by Brad Paisley on September 18th, 2012 and [he] advised me that he had been scammed by a female (later identified as Hope Lyn Jackson)," Lovewell's statement began. "Mr. Paisley also stated that the woman he and his wife had been corresponding with had told them that she had a daughter that was dying of cancer. She led them to believe this was true by sending them emails and photographs that she had actually used from other websites of actual children that were in fact sick and/or dying."

It certainly appeared that Brad Paisley, the country music star, and his wife Kimberly Williams-Paisley, an actress who stars on ABC's "Nashville," had fallen for the same act.

"[Paisley] also told me that [Jackson] had asked him if he would call her dying daughter and sing the song 'Amazing Grace' to her over the telephone and he did," Lovewell's statement continued. "While conducting my investigation I spoke with Hope Jackson and she stated to me that she knowingly made up the story about her having a dying daughter and that she used photographs that she had found on various websites on the Internet to commit this and other scams on unsuspecting people. She stated that she had been conducting this type of activity for at least 4 or 5 years. She also stated that there were other victims."

The arrest had even taken place at the Hotel LaBonte, just as those GPS coordinates had indicated. And it turned out that Hope Jackson was in jail in Douglas on the felony charge of theft of services, which resulted from the fact that Paisley had sung "Amazing Grazing" to her over the phone under false pretenses.

"She used fraud to get him to sing," Kimberly Williams-Paisley later told "Nightline's" David Wright. "That was the crime that was committed."

Once again, she had not directly asked for money.

"I think that's sicker," Brad Paisley said. "I would have welcomed the thought that this was something as simple as a woman scheming."

Instead what emerged over the next 10 months was a picture of a woman who had repeatedly lied to both celebrities and ordinary people with stories of cancer. Sometimes Jackson was supposed to be the sick one, sometimes her children were ailing, and sometimes both. But though she had had multiple run-ins with the law for shoplifting in Montana, her cancer hoaxes never seemed to be about money. She even returned a check that one victim sent to her.

Instead, she appeared to be looking for attention and an emotional connection.

"It is stage 4 neuroblastoma," she wrote by text message to Carmen Hope Thomas, a gospel singer. "The worst news we could have gotten. Ollie has his first chemo in 15 min. It will be a brutal on his little body. I am in the bathroom crying my eyes out. Are you there??"

My colleague, "Nightline" producer Sally Hawkins, was tremendously helpful following up on leads to come up with a growing list of victims, including the band Little Big Town, the American Idol contestant and Grammy winner Mandisa, and Kate Gosselin, the reality television star.

As various victims shared their emails with the hoaxer, patterns started to emerge. The cancer was often neuroblastoma. Jackson peppered her correspondence with certain favorite phrases like "angel wings." Jackson's introductory email to Christian recording artist Natalie Grant was almost identical to the email used to lure in Kimberly Williams-Paisley.

Jackson appeared to play multiple parts in phone calls. Sometimes she was the mother, and sometimes the daughter. Grant said that she noticed that something about the little girl's voice seemed off when she spoke to her over the phone.

"I actually was mad at myself for even having those thoughts because I thought, 'Natalie, how could you be thinking this?'" Grant said. "This is a little girl who's on her deathbed, taking her final breaths, how could you even be questioning this?"

Gosselin had even dedicated an episode of "Jon & Kate Plus 8" to a woman who had supposedly died of cancer. In the credits, it said, "In Loving Memory of Hope." My colleague Sally Hawkins reached Gosselin by email, and Sally was actually the person to tell her that her conversations with the real Hope Jackson, which had lasted for months, were based on lies.

"This is the first email in a LONG time that I read, and realized my jaw had actually dropped and my mouth was hanging open," Gosselin wrote back.

Other calls were far more difficult to make. There were the other people who got caught up in this hoax, the real families who had lost children only to have their tragedies and photos stolen by Jackson. The Skees family of Florida and the Thomas family of Ohio generously shared their stories with us and welcomed us into their homes so that we could learn about two of the real children in the photos, Ellie Skees and Christi Thomas.

Angela Thomas, Christi's mother, said her daughter was a luminous child who spread love and joy to total strangers.

"She just had an infectious smile where people would just fall in love with Christi," Thomas said.

She hopes that, despite the hoax, celebrities will continue to reach out to others.

"I hope they haven't had their hearts hardened ... so that they won't do those things that a sick child would certainly ask for or would want," Thomas said.

Sarah Skees was one of the first people I spoke to while researching this story, and I visited her home in November of last year. She spoke of her daughter, Ellie, a young girl with a great sense of humor who loved animals, Egypt, art and especially, other people.

A year later, as new discoveries unfolded, Sarah Skees sounded moved to learn that her daughter's photos had ended up in the hands of Natalie Grant even by way of a hoax. Grant sings the song "Held," about a mother who loses a child, which Sarah listened to repeatedly while grieving.

"That song has been incredibly meaningful to me," she said. "I have often wished I could thank her for that."

Both mothers said that they were motivated to speak out about Jackson to raise awareness about pediatric cancer. Skees urged those who want to learn more about the issues that are specific to childhood cancer to watch a film called "The Truth 365."

Reaching the woman behind the hoax, even after we learned her identity, was not easy. Jackson posted bail and got out in January, but it was hard to get in touch with her because she used multiple phone numbers that she changed frequently. But after a couple of in-person visits to the courthouse during her legal proceedings -- she pled guilty and got five years probation -- Jackson agreed to talk to us on camera.

"I can look back on it now and see how much pain all my actions have caused," she told "Nightline's" David Wright, "but it'll never make it right."

For the most part, she did not want to name other famous victims, but she did say that she had spoken to Johnny Depp once on the phone using the same sob story, and received some "board games," "blankets" and "lunch boxes" from him. His representative declined to comment.

She insisted that her stories were not about gaining material goods but instead "love" and "acceptance" that she went about trying to get "in the wrong way."

We asked University of Alabama psychiatrist Dr. Marc Feldman to come to the edit room to watch Jackson's interview. Feldman coined the term "Munchausen by Internet" in 2000 to describe a mental illness that involves feigning or exaggerating illnesses online. Though Jackson is not his patient, he said that she clearly seems to be clear example of this condition.

"The person is embroiled in the day-to-day minutiae of telling their stories to others on the Internet," he said, describing the typical Munchausen by Internet patient, "but they're overlooking the deep-seated emotional pain that may be a depression."

The last time we spoke to Jackson in late October, she said that she is in counseling twice a week in Douglas and on several medications for depression and anxiety. Court documents had also revealed a diagnosis of depression. She said that there are issues from her childhood that she is now working to resolve.

"Everybody has something in their past that's happened to them, you know, that's not good," Jackson said. "That doesn't mean they go out and hurt other people."

We continue to find remnants of Jackson's hoaxes all over the Internet, from this memorial website to a tweet from Glee star Naya Rivera that appears to reference one of Jackson's familiar story lines. We wonder how many other people will come forward after this piece airs to say that they, too, heard from Jackson or one of her aliases.

In the end, it was a far cry from a financial scheme that led Hope Jackson to lie to so many people. Many of her victims say that they hope that Jackson gets the help and emotional support that she needs. They also conveyed to us their heartfelt desire that this strange, sad tale not dampen people's willingness to respond to strangers in need.

"That's a huge part of why I do what I do is so that I can use my influence for good and to help," Kimberly Williams-Paisley said. "And if there is someone that I can help, I will help."